Although not exclusively, said detection device is intended more particularly to detect a laser pulse of very short duration (for example 20 ns) which is emitted in an ambient luminous environment of variable illumination, at a predetermined frequency (for example 10 Hz). By way of illustration, the laser pulse to be detected may be emitted by a laser source which is pointed at a target, for example a tank, in order to designate it so that it can be located by a weapon system, such as a missile, which is equipped with said detection device and which is intended to destroy this target. For this purpose, said laser pulse detection device is for example associated with the homing head of the missile, is disposed fixedly on said missile and observes the space forward of said missile. The information relating to the locating of the target and which is generated by this detection device, is provided to the homing head which uses it to guide the missile onto the target.
A considerable drawback relating to the use of such a detection device resides in the presence, in addition to the low-energy and short-duration laser pulses that one wishes to detect, of numerous illuminations, in particular solar, which form luminous background noise, often making it very difficult to detect said sought-after laser pulses.
Patent FR-2 753 796 discloses a photosensitive detector for the detection of luminous flashes, this photosensitive detector comprising:                a photosensitive diode capable of transforming the luminous energy received into an electric current or electrical signal; and        a means of processing the electrical signals generated by said photosensitive diode, said processing means comprising a differentiator electrical circuit which:                    on the one hand, strengthens the electrical signals exhibiting a fast rise time and corresponding to a sought-after luminous flash received by the photosensitive diode; and            on the other hand, attenuates the electrical signals corresponding to illuminations which vary more slowly in intensity, of said photosensitive diode.                        
This photosensitive detector therefore makes it possible to demarcate a luminous flash with respect to the luminous background noise.
However, when one wishes to make a photosensitive detector of this type, for an application such as the aforesaid, several constraints are encountered, and in particular:                a size constraint. The detector should in fact exhibit a much reduced size, for example 70 μm×70 μm;        a cost constraint. To be economical, the detector should exhibit a very low fabrication cost; and        a technical constraint. The detector should be able to detect and extract from the luminous background a laser pulse of short duration (for example 20 ns) and of very low energy (for example 10−13 J).        